Updated on 2025/04/10
Phd (Computer Science) （ 2006.3 The University of Tokyo ）
Quantum computing
Computational complexity
Distributed computing
Algorithms
Informatics / Theory of informatics
Distributed Computing
Quantum computing
Computational Complexity
Algorithms
Nagoya University Graduate School of Mathematics Professor
2022.4
Nagoya University Graduate School of Mathematics Associate professor
2019.10 - 2022.3
Kyoto University Graduate School of Informatics Designated associate professor
2016.4 - 2019.9
The University of Tokyo Graduate School of Information Science and Technology Designated associate professor
2012.4 - 2016.3
The University of Tokyo Graduate School of Information Science and Technology Designated lecturer
2009.4 - 2012.3
INFORMATION PROCESSING SOCIETY OF JAPAN
EATCS
ACM SIGACT
ACM
日本数学会
Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC) Steering committee chair
2024.10 - 2025.9
Committee type：Academic society
Editorial board member
2023.1
Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC) Steering committee member
2022.10
26th Conference on Quantum Information Processing (QIP 2023) Program committee chair
2022.5 - 2023.2
ACM Transactions on Quantum Computing Editorial board member
2019.6
Computational Complexity Editorial board member
2016.6
Committee type：Academic society
ACM-SIAM Symposium on Discrete Algorithms (SODA24) Program Committee member
2024.2 - 2024.7
Committee type：Academic society
51st EATCS International Colloquium on Automata, Languages and Programming (ICALP 2024) Program Committee member
2024.2 - 2024.7
Committee type：Academic society
51st EATCS International Colloquium on Automata, Languages and Programming (ICALP 2024) Program Committee member
2024.2 - 2024.7
Committee type：Academic society
ACM-SIAM Symposium on Discrete Algorithms (SODA24) Program Committee member
2023.7 - 2024.1
Committee type：Academic society
組織委員
2023.4 - 2026.3
Committee type：Academic society
2023 Computational Complexity Conference (CCC 2023) Program Committee member
2023.2 - 2023.7
Committee type：Academic society
2023 Computational Complexity Conference (CCC 2023) Program Committee member
2023.2 - 2023.7
The International Symposium on Quantum Science, Technology and Innovation (Quantum Innovation) 組織委員
2023
Committee type：Government
Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC) Steering committee member
2022.10
26th Conference on Quantum Information Processing (QIP 2023) Program committee chair
2022.5 - 2023.2
17th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2022) Program committee chair
2021.10 - 2022.7
電子情報通信学会 コンピュテーション研究会専門委員
2016.6 - 2022.5
Committee type：Academic society
51st EATCS International Colloquium on Automata, Languages and Programming Program Committee member
Committee type：Academic society
NISTEP Award 2017
2017.11 MEXT
Francois Le Gall
ISSAC 2014 Distinguished Paper Award
2014.7 ACM-SIGAL
Faster Rectangular Matrix Multiplication by Combination Loss Analysis Reviewed
François Le Gall
Proceedings of the 2024 Annual ACM-SIAM Symposium on Discrete Algorithms (SODA) page： 3765 - 3791 2024.1
No Distributed Quantum Advantage for Approximate Graph Coloring. Reviewed
Xavier Coiteux-Roy, Francesco D'Amore 0001, Rishikesh Gajjala, Fabian Kuhn, François Le Gall, Henrik Lievonen, Augusto Modanese, Marc-Olivier Renou, Gustav Schmid, Jukka Suomela
Proceedings of the 56th ACM Symposium on Theory of Computing (STOC 2024) page： 1901 - 1910 2024
Sevag Gharibian, François Le Gall
Proceedings of the 54th ACM Symposium on Theory of Computing (STOC 2022) page： 19 - 32 2022
Distributed Quantum Proofs for Replicated Data. Reviewed
Pierre Fraigniaud, François Le Gall, Harumichi Nishimura, Ami Paz
Proceedings of the 12th Innovations in Theoretical Computer Science conference (ITCS 2021) page： 28 - 20 2021
Tight Distributed Listing of Cliques. Reviewed
Keren Censor-Hillel, Yi-Jun Chang, François Le Gall, Dean Leitersdorf
Proceedings of the 32nd ACM-SIAM Symposium on Discrete Algorithms (SODA 2021) page： 2878 - 2891 2021
Barriers for rectangular matrix multiplication Reviewed International coauthorship Open Access
Matthias Christandl, François Le Gall, Vladimir Lysikov, Jeroen Zuiddam
Computational Complexity Vol. 34 ( 1 ) page： 4 - 4 2025.1
Robust Dequantization of the Quantum Singular Value Transformation and Quantum Machine Learning Algorithms Reviewed Open Access
François Le Gall
Computational Complexity, Vol. 34 ( 1 ) page： 2 - 2 2025.1
Quantum Simultaneous Protocols Without Public Coins Using Modified Equality Queries Reviewed International coauthorship
François Le Gall, Oran Nadler, Harumichi Nishimura, Rotem Oshman
Proceedings of the 28th International Conference on Principles of Distributed Systems (OPODIS 2024) page： 34:1 - 34:20 2024.12
Seunghoan Song, François Le Gall, Masahito Hayashi
EPJ Quantum Technology Vol. 11 ( 1 ) 2024.9
Hugo Delavenne, François Le Gall
Quantum Information and Computation Vol. 24 ( 9&10 ) page： 754 - 765 2024.9
Sevag Gharibian, François Le Gall
SIAM Journal on Computing Vol. 52 ( 4 ) page： 1009 - 1038 2023.8
Quantum Meets Fine-Grained Complexity: Sublinear Time Quantum Algorithms for String Problems. Reviewed
François Le Gall, Saeed Seddighin
Algorithmica Vol. 85 ( 5 ) page： 1251 - 1286 2023.5
Distributed Quantum Interactive Proofs. Reviewed
François Le Gall, Masayuki Miyamoto, Harumichi Nishimura
Proceedings of the 40th International Symposium on Theoretical Aspects of Computer Science (STACS 2023) page： 42:1 - 42:21 2023
Distributed Merlin-Arthur Synthesis of Quantum States and Its Applications. Reviewed
François Le Gall, Masayuki Miyamoto, Harumichi Nishimura
Proceedings of the 48th International Symposium on Mathematical Foundations of Computer Science (MFCS 2023) page： 63 - 15 2023
Improved Hardness Results for the Guided Local Hamiltonian Problem. Reviewed
Chris Cade, Marten Folkertsma, Sevag Gharibian, Ryu Hayakawa, François Le Gall, Tomoyuki Morimae, Jordi Weggemans
Proceedings of the 50th EATCS International Colloquium on Automata, Languages and Programming (ICALP 2023) page： 32:1 - 32:19 2023
Quantum Distributed Computing: Potential and Limitations (Invited Talk).
François Le Gall
OPODIS page： 2 - 1 2023
Quantum Distributed Algorithms for Detection of Cliques. Reviewed
Keren Censor-Hillel, Orr Fischer, François Le Gall, Dean Leitersdorf, Rotem Oshman
Proceedings of the 13th Innovations in Theoretical Computer Science conference (ITCS 2022) page： 35 - 25 2022
Quantum Meets Fine-Grained Complexity: Sublinear Time Quantum Algorithms for String Problems. Reviewed
François Le Gall, Saeed Seddighin
Proceedings of the 13th Innovations in Theoretical Computer Science conference (ITCS 2022) page： 97 - 23 2022
Quantum approximate counting for Markov chains and collision counting. Reviewed
Francois Le Gall, Iu-Iong Ng
Quantum Information & Computation Vol. 22 ( 15&16 ) page： 1261 - 1279 2022
An Optimal Oracle Separation of Classical and Quantum Hybrid Schemes. Reviewed
Atsuya Hasegawa, François Le Gall
Proceedings of the 33rd International Symposium on Algorithms and Computation (ISAAC 2022) page： 6 - 14 2022
Bounds on Oblivious Multiparty Quantum Communication Complexity. Reviewed
François Le Gall, Daiki Suruga
Proceedings of the 15th Latin American Theoretical Informatics Symposium (LATIN 2022) page： 641 - 657 2022
Brief Announcement: Distributed Quantum Interactive Proofs. Reviewed
François Le Gall, Masayuki Miyamoto, Harumichi Nishimura
Proceedings of the 36th International Symposium on Distributed Computing (DISC 2022) page： 48 - 3 2022
Test of Quantumness with Small-Depth Quantum Circuits. Reviewed
Shuichi Hirahara, François Le Gall
Proceedings of the 46th International Symposium on Mathematical Foundations of Computer Science (MFCS 2021) page： 59 - 15 2021
Quantum Logarithmic Space and Post-Selection. Reviewed
François Le Gall, Harumichi Nishimura, Abuzer Yakaryilmaz
Proceedings of the 16th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2021) page： 10 - 17 2021
Quantum communication complexity of distribution testing. Reviewed
Aleksandrs Belovs, Arturo Castellanos, Francois Le Gall, Guillaume Malod, Alexander A. Sherstov
Quantum Information & Computation Vol. 21 ( 15&16 ) page： 1261 - 1273 2021
Quantum Advantage with Shallow Circuits Under Arbitrary Corruption. Reviewed
Atsuya Hasegawa, François Le Gall
Proceedings of the 32nd International Symposium on Algorithms and Computation (ISAAC 2021) page： 74 - 16 2021
Lower Bounds for Induced Cycle Detection in Distributed Computing. Reviewed
François Le Gall, Masayuki Miyamoto
Proceedings of the 32nd International Symposium on Algorithms and Computation (ISAAC 2021) page： 58 - 19 2021
Quantum Distributed Algorithm for Triangle Finding in the CONGEST Model. Reviewed
Taisuke Izumi, François Le Gall, Frédéric Magniez
37th International Symposium on Theoretical Aspects of Computer Science (STACS 2020) Vol. 154 page： 23 - 13 2020
Barriers for Rectangular Matrix Multiplication.
Matthias Christandl, François Le Gall, Vladimir Lysikov, Jeroen Zuiddam
Electron. Colloquium Comput. Complex. Vol. 27 page： 30 - 30 2020
Quantum-Inspired Classical Algorithms for Singular Value Transformation. Reviewed
Dhawal Jethwani, François Le Gall, Sanjay K. Singh
Proceedings of the 45th International Symposium on Mathematical Foundations of Computer Science (MFCS 2020) page： 53 - 14 2020
Quantum Speedup for the Minimum Steiner Tree Problem. Reviewed
Masayuki Miyamoto, Masakazu Iwamura, Koichi Kise, François Le Gall
Proceedings of the 26th International Computing and Combinatorics Conference (COCOON 2020) page： 234 - 245 2020
On Distributed Listing of Cliques. Reviewed
Keren Censor-Hillel, François Le Gall, Dean Leitersdorf
Proceedings of the 39th ACM Symposium on Principles of Distributed Computing (PODC 2020) page： 474 - 482 2020
Fast Distributed Algorithms for Girth, Cycles and Small Subgraphs. Reviewed
Keren Censor-Hillel, Orr Fischer, Tzlil Gonen, François Le Gall, Dean Leitersdorf, Rotem Oshman
Proceedings of the 34th International Symposium on Distributed Computing (DISC 2020) page： 33 - 17 2020
Brief Announcement: Distributed Quantum Proofs for Replicated Data. Reviewed
Pierre Fraigniaud, François Le Gall, Harumichi Nishimura, Ami Paz
Proceedings of the International Symposium on Distributed Computing (DISC 2020) page： 43 - 3 2020
Finding Small and Large $k$-Clique Instances on a Quantum Computer Reviewed
Sara Ayman Metwalli, Francois Le Gall, Rodney Van Meter
IEEE Transactions on Quantum Engineering Vol. 1 page： 1 - 11 2020
Average-Case Quantum Advantage with Shallow Circuits. Reviewed
François Le Gall
34th Computational Complexity Conference, CCC 2019, July 18-20, 2019, New Brunswick, NJ, USA. page： 21:1-21:20 2019
Quantum Query Complexity of Unitary Operator Discrimination. Reviewed
Akinori Kawachi, Kenichi Kawano, Francois Le Gall, Suguru Tamaki
IEICE Transactions Vol. 102-D ( 3 ) page： 483 - 491 2019
Quantum Distributed Algorithm for the All-Pairs Shortest Path Problem in the CONGEST-CLIQUE Model. Reviewed
Taisuke Izumi, François Le Gall
Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing, PODC 2019, Toronto, ON, Canada, July 29 - August 2, 2019. page： 84 - 93 2019
Quantum Advantage for the LOCAL Model in Distributed Computing. Reviewed
François Le Gall, Ansis Rosmanis, Harumichi Nishimura
36th International Symposium on Theoretical Aspects of Computer Science, STACS 2019, March 13-16, 2019, Berlin, Germany page： 49:1-49:14 2019
Quantum Advantage for the LOCAL Model in Distributed Computing
Le Gall Francois, Nishimura Harumichi, Rosmanis Ansis
36TH INTERNATIONAL SYMPOSIUM ON THEORETICAL ASPECTS OF COMPUTER SCIENCE (STACS 2019) 2019
Generalized Quantum Arthur-Merlin Games. Reviewed
Hirotada Kobayashi, François Le Gall, Harumichi Nishimura
SIAM J. Comput. Vol. 48 ( 3 ) page： 865 - 902 2019
Improved rectangular matrix multiplication using powers of the coppersmith-winograd tensor Reviewed
François Le Gall, Florent Urrutia
Proceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms page： 1029 - 1046 2018
Sublinear-Time Quantum Computation of the Diameter in CONGEST Networks. Reviewed
François Le Gall, Frédéric Magniez
Proceedings of the 2018 ACM Symposium on Principles of Distributed Computing, PODC 2018, Egham, United Kingdom, July 23-27, 2018 page： 337 - 346 2018
Interactive Proofs with Polynomial-Time Quantum Prover for Computing the Order of Solvable Groups. Reviewed
François Le Gall, Tomoyuki Morimae, Harumichi Nishimura, Yuki Takeuchi
43rd International Symposium on Mathematical Foundations of Computer Science, MFCS 2018, August 27-31, 2018, Liverpool, UK page： 26:1-26:13 2018
Quantum Algorithm for Triangle Finding in Sparse Graphs Reviewed
Francois Le Gall, Shogo Nakajima
ALGORITHMICA Vol. 79 ( 3 ) page： 941 - 959 2017.11
MODIFIED GROUP NON-MEMBERSHIP IS IN PROMISE-AWPP RELATIVE TO GROUP ORACLES Reviewed
Tomoyuki Morimae, Harumichi Nishimura, Francois Le Gall
QUANTUM INFORMATION & COMPUTATION Vol. 17 ( 3-4 ) page： 242 - 250 2017.3
Multiparty Quantum Communication Complexity of Triangle Finding. Reviewed
François Le Gall, Shogo Nakajima
12th Conference on the Theory of Quantum Computation, Communication and Cryptography, TQC 2017, June 14-16, 2017, Paris, France page： 6:1-6:11 2017
Triangle Finding and Listing in CONGEST Networks. Reviewed
Taisuke Izumi, François Le Gall
Proceedings of the ACM Symposium on Principles of Distributed Computing, PODC 2017, Washington, DC, USA, July 25-27, 2017 page： 381 - 389 2017
Quantum query complexity of unitary operator discrimination Reviewed
Akinori Kawachi, Kenichi Kawano, François Le Gall, Suguru Tamaki
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) Vol. 10392 page： 309 - 320 2017
Quantum Algorithms for Matrix Products over Semirings. Reviewed
François Le Gall, Harumichi Nishimura
Chicago J. Theor. Comput. Sci. Vol. 2017 2017
Probabilistic Logarithmic-Space Algorithms for Laplacian Solvers. Reviewed
Dean Doron, François Le Gall, Amnon Ta-Shma
Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques, APPROX/RANDOM 2017, August 16-18, 2017, Berkeley, CA, USA page： 41:1-41:20 2017
量子アルゴリズムの現状と展望 Invited
ムーンショット目標6 公開シンポジウム 2025.3.4
Beating Grover search for low-energy estimation and state preparation International coauthorship International conference
Harry Buhrman, Sevag Gharibian, Zeph Landau, François Le Gall, Norbert Schuch and Suguru Tamaki
28th Quantum Information Processing Conference (QIP2025)
Space-bounded quantum interactive proof systems International conference
François Le Gall, Yupan Liu, Harumichi Nishimura and Qisheng Wang
Quantum Distributed Computing Invited International conference
Francois Le Gall
IHP Workshop: Quantum technologies for cryptography 2024.12.3
量子アルゴリズム Invited
ルガル フランソワ
ムーンショット目標6 ミニシンポジウム2024 量子コンピュータは、未来をどう変えうるか ～FTQCとそこに至る過程で期待されるアプリケーション～ 2024.10.1
Online Locality Meets Distributed Quantum Computing Invited
Francois Le Gall
2024.9.26
Online Locality Meets Distributed Quantum Computing
Amirreza Akbari, Xavier Coiteux-Roy, Francesco d'Amore, François Le Gall, Henrik Lievonen, Darya Melnyk, Augusto Modanese, Shreyas Pai, Marc-Olivier Renou, Václav Rozhoň, Jukka Suomela
Theory of Quantum Computation, Communication and Cryptography (TQC 2024) 2024.9.12
Theoretical Foundations of Quantum Advantage in Quantum Algorithms Invited
Francois Le Gall
Q2B 2024 Tokyo 2024.7.25
Quantum distributed computing: potential and limitations Invited
Le Gall Francois
2023 CONFERENCE ON PRINCIPLES OF DISTRIBUTED SYSTEMS (OPODIS 2023) 2023.12.7
Quantum Algorithms: Applications and Theoretical Foundations Invited
Francois Le Gall
The 13 th International Symposium for Sustainability by Engineering at Mie University (Research Area C) 2023.11.22
Theoretical Foundations of Quantum Advantage in Quantum Computing Invited
Francois Le Gall
京都大学基礎物理学研究所 創立70周年記念シンポジウム 2023.11.22
Theoretical Foundations of Quantum Advantage for Quantum Algorithms Invited
Francois Le Gall
YIPQS long-term workshop Quantum Information, Quantum Matter and Quantum Gravity 2023.9.20
多人数の量子通信複雑性における新しい手法
第47回量子情報技術研究会 2022.12.8
Distributed Merlin-Arthur Synthesis of Quantum States and Its Applications
第47回量子情報技術研究会 2022.12.8
ガイド付きローカルハミルトニアン問題の計算複雑性の進展
第47回量子情報技術研究会 2022.12.8
Quantum Distributed Computing Invited
Workshop on Advances in Distributed Graph Algorithms (ADGA 2022) 2022.10.24
Theoretical Foundations of Quantum Advantage Invited
Q2B 2022 Tokyo 2022.7.14
分散量子対話型証明
第６回量子ソフトウェア研究会 2022.7.8
Bounds on oblivious multiparty quantum communication complexity
第６回量子ソフトウェア研究会 2022.7.8
Quantum algorithms for large-scale problems Invited International conference
François Le Gall
Quantum Innovation 2021, the International Symposium on Quantum Science, Technology and Innovation 2021.12.9
Tight Distributed Listing of Cliques Invited
2021.3.8
Foundations of Secure Distributed Quantum Computing on Medium-Scale Quantum Computers
Grant number：24H00071 2024.4 - 2029.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (S)
Authorship：Principal investigator
Grant amount：\203450000 （ Direct Cost: \156500000 、 Indirect Cost：\46950000 ）
Quantum Algorithms for Large-Scale Quantum Computers: New Horizons and Applications International coauthorship
Grant number：20H04139 2020.4 - 2024.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
Le Gall Francois
Authorship：Principal investigator Grant type：Competitive
Grant amount：\17290000 （ Direct Cost: \13300000 、 Indirect Cost：\3990000 ）
We investigated the computational power and the applications of large-scale quantum computers. We first rigorously established a quantum advantage (i.e., showed that quantum computers can be faster than supercomputers) for fundamental problems such as high-precision chemistry calculations. We developed several fast quantum distributed algorithms and proved a quantum advantage for distributed computing as well. We also investigated the potential of shallow (i.e., low depth) quantum circuits and demonstrated that they can be significantly more powerful than classical shallow circuits.
Algebraic Complexity Theory: New Approaches and Algorithmic Applications International coauthorship
Grant number：16H05853 2016.4 - 2020.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (A)
Le Gall Francois
Authorship：Principal investigator Grant type：Competitive
Grant amount：\12480000 （ Direct Cost: \9600000 、 Indirect Cost：\2880000 ）
In this research project we developed new techniques based on algebraic complexity theory to solve problems from theoretical computer science. Our main achievements are as follows.
We first developed new approaches to solve algebraic problems, and constructed faster algorithms for rectangular matrix multiplication. We then showed how to apply in a novel way algebraic techniques to several problems from computer science. In particular, via this approach we designed fast distributed algorithms for various computational problems over networks. Finally, we designed several quantum algorithms for graph problems that are faster than the best known algorithms.
Construction of Quantum Computaional Infrastracture towards Quantum Information Society International coauthorship
Grant number：21H04879 2021.4 - 2026.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
Authorship：Coinvestigator(s) Grant type：Competitive
Grant number：20H05966 2020.11 - 2025.3
科学研究費助成事業 学術変革領域研究(A)
山下 茂, 山本 直樹, ルガル フランソワ, 森 立平, 谷 誠一郎, 西村 治道
Authorship：Coinvestigator(s)
量子計算各種モデルにおける計算能力の解析を行う理論的なアプローチと、実際に量子計算機を利用する実践的なアプローチの両面から以下の4項目の研究を行う。
(A) 既存の量子計算モデルの結果を量子・古典協調の観点から、あるいは「弱い」量子計算モデルの観点から再検討・再構築する。
(B) 量子計算に起こりうる現実的なエラーを考慮に入れた計算モデルの検討を進める。
(C) 量子計算の方式に応じて異なる量子回路のモデルを量子・古典協調利用の枠組みの中で検討・評価する。
(D) 量子計算と古典計算を協調して利用する計算アルゴリズムの能力を解析するための計算モデルを検討・評価する。
量子アルゴリズム・計算量・浅層回路と量子コンピュータ実機実験による量子優位性研究 International coauthorship
Grant number：20H00579 2020.4 - 2025.3
日本学術振興会 科学研究費助成事業 基盤研究(A)
今井 浩, 山下 茂, ルガル フランソワ, Avis David
Authorship：Coinvestigator(s) Grant type：Competitive
量子コンピュータの得意な問題を用いて量子計算優越性を達成したとGoogleの研究者らが主張したところである。しかし、その問題は実応用とは無縁であり、IT社会に多大なインパクトを与えるの量子素因数分解計算などの実機実装の研究が重要となっている。本研究では、量子計算が本研究グループの量子浅層回路の計算量理論・実機に対応する量子回路の設計理論・量子非局所性とその組み合わせ構造に着目することにより、理論的に真に高速と示すことができる量子優位性を有する問題の最先端を研究し、量子コンピュータ実機で実証する。このような取り組みで、量子優位性が直接的に実社会に影響を与える新たな問題群を見出す成果を目指す。
3年度目の本研究では、量子優位性を示すことを、研究代表者のところで(1) 分散量子計算を量子機械学習においてスケールアップした実験を実施し、(2) 量子ランダムアクセス符号を拡張した量子緩和を用いた量子近似最適化法に関する研究を理論と実機での実験によって目指した。IBM Quantumの量子コンピュータでの計算も行うことによって、近未来の量子コンピュータの実用性を示す成果をあげることができた。これらの成果はIEEE Quantum Computing and Engineering (QCE) 2023に論文が採択され、(1)の量子機械学習に関する論文の方は、応用面が評価されて応用分野の最優秀論文賞を受賞した。予備的に400超量子ビットのマシンでの結果も得ている。(1)の分散量子計算に関する理論的な研究成果が、分担者のLe Gallによって量子分散対話証明の独自の枠組みの中で得られている。また、研究代表者のところの研究協力者との研究でも、量子ハイブリッドスキームの優位性についても量子計算量理論の観点から示されている。また、(2)の量子最適化での量子緩和の考えは、分担者のDavid Avisによる量子情報の多面体アプローチによる解析を行って得られた成果と、半定値緩和の適用可能性の面で関係している。量子回路設計では分担者の山下の方で、MPMCTゲートを用いた量子回路の最適化、さらに相対位相Toffoliゲートの量子回路設計において導入された相対位相をキャンセルする新方法を提案するなどの成果を上げることができた。
分散量子機械学習の研究で、その応用面が評価されて、IEEE Quantum Comptuing and Engineeringの国際会議で応用分野での最優秀論文に選ばれている。応用面での量子優位性を示す研究の推進という観点からのもので、このように当初計画より先に進んでいる。
2024年度には、1000量子ビットスケールの量子コンピュータ実機の利用も目指すとともに、量子分散計算がハードウェアの制約からモジュールを接続してスケールアップする方向での実験の研究にも取り組む予定である。理論面の成果とともに、量子優位性を応用・理論両面で示すことを目指す。
Theoretical Research on Quantum Supremacy
Grant number：19F19079 2019.7 - 2021.3
Authorship：Other
Grant number：19H04066 2019.4 - 2023.3
科学研究費助成事業 基盤研究(B)
西村 治道, ルガル フランソワ, 森前 智行, Buscemi F.
Authorship：Coinvestigator(s)
今日の量子計算量理論において，対話型証明の概念は非常に大きな存在となっている．一方で，近年その実装へ向けて社会的注目を集める量子コンピュータはまだ小規模であり，量子メモリや量子通信は依然として高コストである．この状況を鑑みて，本研究では量子計算や量子通信が制限された量子対話型証明や量子計算に動機づけられた古典対話型証明，さらにはその中間的な対話型証明モデルに着目し，それらの対話型証明モデルについての計算量理論を展開する．これにより量子コンピュータの検証問題に対する新しい解決法を提案し，既存の量子対話型証明モデルや量子多項式階層理論を俯瞰的に捉えることができるような包括的成果を得ることを目指す．
Interpolative Expansion of Quantum Protocol Theory International coauthorship
Grant number：16H01705 2016.4 - 2021.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
Takeshi Koshiba
Authorship：Coinvestigator(s) Grant type：Competitive
The computational power of the DQC1 model, which is a formalization of non-universal quantum computation with initialization-hard quantum states, is shown to be superior to classical computation. Many quantum distributed algorithms are developed. Under the standard model for distributed algorithms, efficient quantum protocols for several fundamental problems such as the shortest path problem. Secure quantum delegated computation cannot achieve the perfect security for classical clients. By introducing the notion of rewards in quantum computations, classical verification of having the quantum power of the server is affirmatively settled. This is a game-theoretic solution and gives a novel method in quantum computation.
